The invention relates to a method of determining the own-vehicle position of a motor vehicle having a navigation system fixedly installed in the motor vehicle.
Modern motor vehicles are increasingly equipped with navigation systems, frequently even in series. Navigation systems fixedly installed in motor vehicles determine the position of the motor vehicle in which it is installed (in the following, also called “own-vehicle position”) within the global area imaged on a road map, usually on the basis of GPS or GNSS. Particularly in city center areas with blocks of high buildings, in tunnels or parking garages, the problem may arise that self-localization by GPS/GNSS is not easily possible, for example, because of shadowing and multi-path effects. The same may apply, or may especially apply, when the driver is driving into or out of a parking garage in the center of town.
These types of problems can partly be solved in that additional vehicle sensors (odometry sensors: steering angle, yaw rate, velocity, wheel speeds, etc.) of the respective motor vehicle are used in order to permit an updating of the own-vehicle position by means of a so-called dead reckoning. This occurs also if the GPS/GNSS should fail. However, in this manner, the accuracy of the self-localization can only be improved. Lasting maximum accuracy of the self-localization cannot be guaranteed in this manner—this is particularly true if the GPS/GNSS failures last for a very long time, or if there are several street levels or parallel streets situated side-by-side.
It is an object of the invention to provide a simple improved method for determining the own-vehicle position of a motor vehicle.
This and other objects are achieved by a method of determining the own-vehicle position of a motor vehicle having a navigation system fixedly installed in the motor vehicle, the method includes the steps of: providing a mobile terminal having suitable self-localization; providing an interface for communication-related link-up of the mobile terminal to the motor vehicle; determining the own-terminal position of the mobile terminal by self-localization; transmitting the own-terminal position by way of the interface to the motor vehicle; and taking into account the transmitted own-terminal position when determining the own-vehicle position.
According to the invention, the capability of the mobile terminal for self-localization—which is independent, for example, of shadowing and/or failures of a satellite signal (GPS/GNSS)—is utilized in order to support the self-localization of the navigation system installed in the motor vehicle.
From DE 10 2008 036 681 A1, as an example, a method is known for self-localization based on wireless radio networks, particularly the WLAN, especially for a mobile terminal. As a result of the increasing spread of wireless networks based, for example, on the WLAN standard, these wireless networks present themselves as a basis for new localization methods. In addition to WLAN networks, mobile radio networks (with known locations of the mobile radio masts) also present themselves as wireless radio networks for self-localization. For mobile terminals, it is also known to use a self-localization by way of GPS/GNSS combined with a self-localization by way of wireless radio networks. Since sometimes acceleration sensors and/or compasses are also installed in mobile terminals, even—comparable with the odometry in the case of motor vehicles—motion data of the mobile terminal can be used for the updating of the own-terminal position. The potential of the equipment and processes known from prior art for the self-localization of mobile terminals has, however, so far not been utilized satisfactorily for vehicle navigation.
It is true that complete navigation solutions for motor vehicles are already available on the market, in the case of which a mobile terminal, such as a Smartphone, is used in a vehicle adaptor in the driver's field of vision in order to serve there as a navigation device. However, these solutions are almost exclusively based on the capabilities of the mobile terminal—specifically essentially on its capability to determine the own-terminal position (by means of locating devices arranged in the mobile terminal) and on its capability to graphically display maps and/or navigation instructions (by means of a display of the mobile terminal). This replaces a navigation system fixedly installed in a motor vehicle. In contrast, in the case of the invention, the navigation system fixedly installed in the motor vehicle will not be replaced but be fully utilized and expanded in its capabilities. Capabilities which do not exist according to the state of the art in the case of a navigation system fixedly installed in a motor vehicle will be supplemented by capabilities of the mobile terminal.
Operating input (such as the destination input and/or the selection of the map alignment and/or the selection of the scale) within the scope of a vehicle navigation, which is based on a self-localization taking place according to the invention, preferably takes place exclusively by way of operating devices of the motor vehicle. Graphic and/or acoustic output to the operator within the scope of a vehicle navigation, which is based on a self-localization occurring according to the invention, preferably takes place exclusively by way of output devices (such as the display and/or the loudspeaker) of the motor vehicle.
To this extent, the invention also relates to an overall system suitable for implementing the method according to the invention, composed of a navigation system fixedly installed in the vehicle and a mobile terminal, in the case of which overall system, the own-vehicle position determined while taking into account the transmitted own terminal position, within the scope of a vehicle navigation, is used by the navigation system fixedly installed in the vehicle. In such a case, operating input within the scope of the vehicle navigation can take place exclusively by way of operating devices of the motor vehicle—not by way of the mobile terminal or its operating devices.
In addition, to this extent, the invention also relates to an overall system suitable for implementing the method according to the invention, composed of a navigation system fixedly installed in the vehicle and a mobile terminal, in the case of which overall system, the own-vehicle position determined while taking into account the transmitted own terminal position, within the scope of a vehicle navigation, is used by the navigation system fixedly installed in the vehicle. In such a case, graphic and/or acoustic output to the operator within the scope of the vehicle navigation exclusively takes place by way of output devices of the motor vehicle—not by way of the mobile terminal or its output devices.
In the case of the motor vehicle, a preferably dedicated interface is provided according to the invention for integrating the mobile terminal. By way of this interface, preferably particularly the own-position data of the mobile terminal determined by radio-network-based self-localization can be transmitted to the motor vehicle, particularly to the navigation system fixedly installed in the motor vehicle. From BMW's International Patent Publications WO 2006/063601 A1, WO 2006/063602 A1 and WO 2006/063603 A1, systems and methods are known for integrating a mobile terminal in a motor vehicle. The interface may be wireless or wire-based.
Furthermore, by way of the above-mentioned interface, a request of the motor vehicle or of the navigation system fixedly installed in the motor vehicle can be transmitted to the mobile terminal, by which request the mobile terminal is prompted to send own-terminal position data to the motor vehicle or to the navigation system fixedly installed in the motor vehicle. The motor vehicle can thereby request own-terminal position data particularly (or exclusively) if there is a corresponding demand. In this manner, the data volume transmitted by way of the interface can be reduced. Likewise, in this manner, an improved on-time providing of the required own-terminal position data by the mobile terminal to the motor vehicle can be achieved.
According to a preferred embodiment of the invention, by way of the interface, a request of the motor vehicle is sent to the mobile terminal by which the mobile terminal is prompted to transmit own-terminal position data by way of the interface.
For determining the demand for own-terminal position data, a demand detection unit may be provided in the case of the motor vehicle. This demand detection unit can especially be constructed as a software module of the navigation software of the navigation system fixedly installed in the motor vehicle. The demand can be determined according to the situation. For the determination, different quantities can be analyzed, which can be detected by measuring or exist in the case of the motor vehicle anyhow. Demand can, for example, be recognized when the navigation system fixedly installed in the motor vehicle does not succeed in achieving a self-localization. However, demand can, in principle, also be assumed when a mobile terminal is connected to the interface and/or when the motor vehicle is situated in a populated area (especially in the center of a city). Various indicators of such a demand can contribute to a common measurement for the demand.
Thus, according to a further preferred embodiment of the invention, a demand or a measurement of the demand for receiving own-terminal position data is determined in the case of the motor vehicle, and a request of the motor vehicle is sent to the mobile terminal if the demand exists or if the measurement of the demand exceeds a predefined demand threshold.
The accuracy—to be determined beforehand—of a position signal based on satellite signals and present in the motor vehicle can be used as an indicator of, or as an influential quantity on, a measurement of the demand. If the accuracy falls below, for example, a predefined accuracy threshold, a demand can be assumed.
As an alternative or in addition to an active request according to the demand, the taking-into-account of the transmitted own-terminal position may also have a different form depending on the situation when determining the own-vehicle position.
For example, own-terminal position data—if available—can basically always be transmitted to the vehicle but can be taken into account only when the navigation system fixedly installed in the motor vehicle does not succeed in a self-localization, when a mobile terminal is connected to the interface, and/or when the motor vehicle is situated in a populated area (especially in the center of a city).
Furthermore, the request and/or the taking into account of an own-terminal position may depend on what accuracy a position signal has that is present in the case of the motor vehicle and is based on satellite signals (particularly GPS/GNSS). If an own-terminal position has been transmitted to the motor vehicle and a position signal based on satellite signals is present at the motor vehicle, their accuracies can be determined, compared, and the more accurate signal can be used. A higher-expenditure fusion of both signals is basically also contemplated.
According to a preferred embodiment of the invention, the accuracy of a position signal based on satellite signals and present at the vehicle is therefore determined, and the transmitted own-terminal position will then only be determined when determining the own-vehicle position if the accuracy of the position signal based on satellite signals falls below a predefined accuracy threshold.
The self-localization according to the invention, in the extreme case, takes place completely unnoticed by the operator or in a manner not noticeably different from that in the case of conventional fixedly installed vehicle navigation systems—unless the operator notices that the overall navigation system (composed of the navigation system fixedly installed in the motor vehicle and of the mobile terminal) presenting itself to him has a better capability for self-localization when the mobile terminal is present in the motor vehicle.
In order to, among other things, signal to the operator that the equipping of his navigation system according to the invention results in an increased value for him, a visual display can be provided, ideally can be integrated in the graphic output of the navigation system, by which it is indicated to the operator that (or when) the own-terminal position is actually received and/or taken into account by the vehicle navigation system. As an alternative or in addition, a corresponding logging can be carried out, and the operator can, for example, later retrieve in a menu-controlled manner whether, when or how often the own-terminal position has actually been received and/or taken into account by the vehicle navigation system.
When the mobile terminal is not present in the motor vehicle or when, because of a lack of radio network signals, it does not succeed in self-localization, the self-localization of the navigation system fixedly installed in the motor vehicle will preferably take place in a manner known per se exclusively based on satellite signals and, if necessary, odometry.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.